<%= form_for(:search, :url => search_index_path, :html => { :method => :get }) do |f| %>
    <% if @email.nil? %>
 		<%= f.text_field :email, :placeholder => t('search.form.search_by_email') %>
 	<% else %>
 		<%= f.text_field :email, :placeholder => t('search.form.search_by_email'), :value => @email %>
 	<% end %>

    <%= f.submit t('search.search'), class: 'no_margin_right' %>
<% end %>